An organic electroluminescence device (hereinafter the term “electroluminescence” is often abbreviated as “EL”) is a self-emission device utilizing the principle that a fluorescent substance emits light by the recombination energy of holes injected from an anode and electrons injected from a cathode when an electric field is impressed.
An organic EL device has attained a remarkable progress. In addition, the organic EL device is expected to be applied to a wide range of applications due to its capability of being driven at a low voltage, a high luminance, variety in emission wavelength, high-speed response, its capability of producing an emitting device which is thin and light in weight, or the like.
Emitting materials used in an organic EL device have been actively studied, since they exert large effects on the color of light emitted by the device and emission life.
Examples of the emission materials include chelate complexes such as tris(8-quinolinolate)aluminum complexes, cumarin derivatives, tetraphenylbutadiene derivatives, bisstyrylarylene derivatives and oxadiazole derivatives. Due to these emitting materials, emission in a visible range from blue to red can be obtained.
In addition, studies have been made on the use of a phosphorescence compound and the use of triplet energy in emission. For example, it is known that an organic EL device using an iridium complex as an emitting material shows a high degree of luminous efficiency.
Patent Documents 1 to 4 each disclose an organic EL device using a chrysene derivative. By using the materials disclosed in these patent documents, the luminous efficiency and lifetime of an organic EL device can be improved. However, further improvements in efficiency and prolongation of lifetime have been required.    Patent Document 1: WO2004/016575    Patent Document 2: JP-A-2000-273055    Patent Document 3: JP-A-2006-52323    Patent Document 4: JP-A-2006-52324
The object of the invention is to provide an organic material which is preferable as a material for an organic EL device. In particular, the invention is aimed at providing a material, as a material for a phosphorescent organic EL device, which has a high efficiency and a long lifetime.